Minecraft Server Optimization Guide

If your Minecraft server stutters, drops TPS, or struggles at 30 players when it should hold 100, the cause is almost always one of five things: too many entities, too many chunks loaded, GC pauses, a slow disk, or a CPU that can't keep up. Here's how to fix each.

1. Measure before you tune

Install Spark (spark.lucko.me). Run:

/spark profiler start --thread main
# wait through a slow period
/spark profiler stop

The flame graph tells you exactly which class is eating the main thread.

2. Paper config , the must-change knobs

In config/paper-global.yml and config/paper-world-defaults.yml:

# paper-world-defaults.yml
chunks:
  max-auto-save-chunks-per-tick: 24
entities:
  spawning:
    per-player-mob-spawns: true
    spawn-limits:
      monster: 50
      animal: 6
      water-animal: 3
collisions:
  max-entity-collisions: 2

per-player-mob-spawns is the single biggest win on most servers , it stops the global mob cap from being eaten by one AFK player.

3. View distance vs simulation distance

In server.properties:

view-distance=8
simulation-distance=6

view-distance = how many chunks the client sees. simulation-distance = how many chunks tick (mobs, redstone, growth). Simulation distance is the expensive one. 6 is the sweet spot for most servers.

4. Entity caps and item merging

Items dropping in massive farms kill TPS. In Paper config:

entities:
  spawning:
    despawn-ranges:
      monster: {soft: 24, hard: 64}
  item-merge-radius: 4.0
  exp-merge-radius: 4.0

5. Redstone

If a single redstone farm tanks the whole server, install Alternate Current (a faster redstone implementation). It's a server jar plugin , drop in and forget.

6. JVM flags , Aikar's flags

The community-standard JVM flags for any modern Paper server:

java -Xms8G -Xmx8G \
  -XX:+UseG1GC -XX:+ParallelRefProcEnabled \
  -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions \
  -XX:+DisableExplicitGC -XX:+AlwaysPreTouch \
  -XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 \
  -XX:G1HeapRegionSize=8M -XX:G1ReservePercent=20 \
  -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 \
  -XX:InitiatingHeapOccupancyPercent=15 \
  -XX:G1MixedGCLiveThresholdPercent=90 \
  -XX:G1RSetUpdatingPauseTimePercent=5 \
  -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem \
  -XX:MaxTenuringThreshold=1 \
  -Dusing.aikars.flags=https://mcflags.emc.gs \
  -Daikars.new.flags=true \
  -jar paper.jar nogui

Set Xms = Xmx. Don't allocate more than 50% of system RAM.

7. Disk and chunks

Pre-generate the world to avoid live chunk-gen lag:

/chunky world world
/chunky radius 5000
/chunky start

Use Chunky at server startup before opening to players. Saves enormous amounts of mid-play stutter.

8. The plugins that always need tuning

• EssentialsX: disable per-player UUID lookups in config.yml.
• CoreProtect: on MySQL, schedule purges , see CoreProtect guide.
• WorldGuard: avoid global flags on huge worlds.
• MythicMobs: avoid skills with ~onTimer shorter than 20 ticks.

9. The 5 quick wins checklist

1. Switch to Paper if you're on Spigot or vanilla.
2. Set simulation-distance: 6.
3. Enable per-player-mob-spawns: true.
4. Apply Aikar's flags.
5. Pre-generate world borders with Chunky.

Prefer a server that's already tuned for this? Astroworld MC runs a hand-optimised Paper stack with custom plugins so you can just log in and play.